Surgical stapling device

ABSTRACT

A surgical stapling device including a self-righting anvil assembly is disclosed. The anvil assembly includes an anvil center rod and a pivotable anvil head. The surgical stapling device includes an anvil retainer assembly having a locking member in the form of a trocar for moving the anvil head from its tilted position to its operative position upon attachment of the anvil assembly to the stapling device. A cam member is provided to retain the locking member in a first or locked position and, thus, the anvil head in the operative position until after the stapling device has been fired. In another embodiment, a tiltable anvil assembly for use with a surgical stapling device is disclosed. The anvil assembly includes a center rod and a head assembly which is pivotally secured to the center rod. The head assembly includes a housing, a post, an anvil plate and a backup member. The backup member is movably positioned about the post from a first position preventing pivotal movement of the head assembly to a second position permitting pivotal movement of the head assembly. A retainer member is positioned between the backup member and the housing to prevent movement of the backup member from its first position to its second position until a predetermined force has been applied to the backup member. In another embodiment, a passive lockout mechanism is disclosed which is operably associated with a trigger lock on the handle assembly of the surgical stapling device. The passive lockout mechanism is positioned to prevent movement of the anvil assembly in relation to the shell assembly of the device from an approximated position to an unapproximated position when the trigger lock is in an unlocked position.

This application claims priority from U.S. provisional application Ser.No. 60/512,482 filed Oct. 17, 2003, and 60/512,405 filed Oct. 17, 2003,the entirety of each of which is incorporated herein by reference. Thisapplication also claims priority from U.S. provisional application Ser.No. ______, titled “Surgical Stapling Device”, filed on Oct. 8, 2004under Express Mail No. EV517670269US and U.S. provisional applicationSer. No. ______, titled “Surgical Stapling Device With Self-RightingAnvil Head”, filed on Oct. 8, 2004 under Express Mail No. EV517670224,the entirety of each of which is incorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates generally to a surgical stapling devicefor applying surgical staples to body tissue. More particularly, thepresent disclosure relates to a surgical stapling device suitable forperforming circular anastomosis of hollow tissue organs.

2. Background to Related Art

Anastomosis is the surgical joining of separate hollow organ sections.Typically, an anastomosis procedure follows surgery in which a diseasedor defective section of hollow tissue is removed and the remaining endsections are to be joined. Depending on the desired anastomosisprocedure, the end sections may be joined by either circular,end-to-side or side-to-side organ reconstruction methods.

In a circular anastomosis procedure, the two ends of the organ sectionsare joined by means of a stapling instrument which drives a circulararray of staples through the end section of each organ section andsimultaneously cores any tissue interior of the driven circular array ofstaples to free the tubular passage. Examples of instruments forperforming circular anastomosis of hollow organs are described in U.S.Pat. Nos. 6,053,390, 5,588,579, 5,119,983, 5,005,749, 4,646,745,4,576,167, and 4,473,077, each of which is incorporated herein in itsentirety by reference. Typically, these instruments include an elongatedshaft having a handle portion at a proximal end of the elongated body toactuate the instrument and a staple holding component disposed at adistal end of the elongated body. An anvil assembly including an anvilrod with attached anvil head is mounted to the distal end adjacent thestaple holding component. Opposed end portions of tissue of the organsto be stapled are clamped between the anvil head and the staple holdingcomponent. The clamped tissue is stapled by driving one or more staplesfrom the staple holding component so that the ends of the staples passthrough the tissue and are deformed by the anvil head.

Instruments for performing circular anastomosis procedures having anvilassemblies which are pivotable from an operative position to a tilted ornon-operative position are known in the art. Such pivotable anvilassemblies lessen the trauma to a patient during insertion and/orremoval of the anvil assembly into or from a body lumen.

During some procedures using such instruments, it is desirable to insertthe anvil assembly of the instrument into a body lumen in the tiltedposition, return the anvil assembly to the operative position to performthe anastomosis procedure, and thereafter return the anvil assembly toits tilted position for removal of the anvil assembly and/or instrumentfrom the body lumen. During other procedures, it is desirable to insertthe anvil assembly into a body lumen in its operative position and movethe anvil assembly to its tilted position prior to removal from the bodylumen. In each of these procedures, it would be desirable for the anvilassembly to move automatically to its desired position.

Accordingly, a continuing need exists in the art for an improvedstapling device having a tiltable anvil assembly which can achieve theabove-mentioned objectives.

SUMMARY

In accordance with the present disclosure, a surgical stapling device isdisclosed for performing circular anastomoses. The surgical staplingdevice includes a handle portion or assembly, a body portion and a headportion including an anvil assembly and a shell assembly. The handleportion can include a rotatable approximation knob for approximating theanvil and shell assemblies and a firing trigger for actuating a firingmechanism for ejecting staples positioned within the shell assembly fromthe shell assembly. In one embodiment, the firing trigger forms one linkof a two bar linkage provided to actuate the firing mechanism. The twobar linkage provides the device with an improved mechanical advantage toreduce the firing forces required to fire the device.

In one embodiment, the head portion includes an anvil assembly which isnormally in a tilted position and will automatically pivot to anoperative position when the anvil assembly is attached to the surgicalstapling device and return to the tilted position after the device hasbeen fired and unapproximated. The tiltable anvil provides a reducedanvil profile to reduce trauma during insertion and removal of thedevice from a body lumen. The anvil assembly includes an anvil head andan anvil center rod. The anvil head is pivotally attached to the anvilcenter rod and is pivotable between the operative position and thetilted position. A biasing member is provided to urge the anvil head toits tilted position. The surgical stapling device includes an anvilretainer assembly having a locking member which is movable from a firstposition to a second position. In its first position, the locking memberis positioned to move the anvil head to its operative upon attachment ofthe anvil head to the surgical stapling device. In its second position,the locking member is positioned to permit the anvil head to pivot toits tilted position. In one embodiment, the anvil retainer assemblyincludes a body portion defining a longitudinal bore and a trocarextending from a distal end of the longitudinal bore. The trocar formsthe locking member and is movable from an advanced position to aretracted position by a biasing member, e.g., a coil spring. In itsadvanced or first position, the distal end of the trocar is positionedto engage a first slide member supported within the anvil center rod tourge the anvil head against the urging of the biasing member from itstilted position to its operative position. In its second position, thetrocar is positioned to permit the anvil head to move from the operativeposition to the tilted position.

In one embodiment, the trocar includes an annular flange and thelongitudinal bore defined by the body portion defines an internalshoulder. The biasing member is positioned between the annular flangeand the shoulder to urge the trocar to its second or proximal position.A pivotable cam member is supported within a slot in the body portion.The cam member is pivotable from a first position to a second position.In the first position of the cam member, a distal finger of the cammember engages a proximal end of the trocar to retain the trocar in itsfirst or distal position. In the second position, the cam member allowsthe trocar to move to its second or proximal position. In oneembodiment, the distal finger includes an angled face such thatengagement between the distal finger of the cam member and the proximalend of the trocar urges the cam member to its second position. A bushingsupported within the shell assembly of the stapling device and a pair ofarms provided on a pusher of the stapling device may be provided toprevent the cam member from moving to its second position until afterthe surgical stapling device has been fired.

In another embodiment, the head portion includes an anvil assemblyhaving a head assembly including a housing, a post, an anvil plate and abackup member. The anvil head assembly is pivotally secured to an anvilcenter rod and movable between an operative position and a tiltedposition. The backup member is slidably positioned about the post and ismovable from a first position to a second position. In its firstposition, the backup member prevents pivotal movement of the headassembly from the operative position to the tilted position. A retainermember is positioned between the head assembly housing and the backupmember to prevent movement of the backup member to its second positionuntil a predetermined force has been applied to the backup member. Theretainer member can include an annular member having a plurality ofdeformable tabs. The deformable tabs are positioned to engage the backupmember such that upon movement of the backup member from its firstposition to its second position, the tabs are deformed. Otherdeformable, compressible, crushable or movement restricting retainingmembers are envisioned.

The surgical stapling device may also include a firing lockout mechanismwhich prevents actuation of the firing trigger until the device has beenapproximated. In one embodiment, the firing lockout mechanism includes atrigger lock and a lockout member which is movably positioned in thehandle assembly. The lockout member prevents movement of the triggerlock from a locked to an unlocked position until the device has beenapproximated.

In another embodiment, the surgical stapling device includes a passivelockout mechanism which prevents movement of the anvil assembly inrelation to the shell assembly after the surgical stapling device hasbeen approximated and the trigger lock has been moved to its unlockedposition. The passive lockout mechanism includes an locking plate and abiasing member. The locking plate is releasably coupled to the triggerlock and includes a locking tab and a release tab. Movement of thetrigger lock from its locked position to its unlocked position effectsmovement of the locking plate to a position in which the locking tabprevents unapproximation of the anvil assembly in relation to the shellassembly. The locking tab is moved to a position permittingunapproximation of the anvil assembly in relation to the shell assemblyautomatically upon actuation of the firing trigger.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed surgical stapling deviceare disclosed herein with reference to the drawings wherein:

FIG. 1 is a top side perspective view from the proximal end of thepresently disclosed surgical stapling device in the unapproximatedposition;

FIG. 2 is a top side perspective view from the distal end of thesurgical stapling device shown in FIG. 1;

FIG. 3 is a side perspective exploded view of the handle assembly of thesurgical stapling device shown in FIG. 1;

FIG. 3A is a top perspective view of the indicator of the handleassembly shown in FIG. 3;

FIG. 3B is a side perspective view of an alternate embodiment of thetrigger lock of the handle assembly shown in FIG. 3;

FIG. 4 is a side perspective view from the top of the handle assembly ofthe surgical stapling device shown in FIG. 1 with a handle sectionremoved;

FIG. 5 is a side perspective view from the bottom of the handle assemblyof the surgical stapling device shown in FIG. 4;

FIG. 6 is a side perspective exploded view of the central body portionand distal head portion of the surgical stapling device shown in FIG. 1;

FIG. 7 is an enlarged side perspective of the anvil retainer and distalend of the band portions of the central body portion shown in FIG. 6;

FIG. 7A is a side perspective view from the proximal end of an alternateembodiment of the anvil retainer shown in FIG. 7,

FIG. 7B is a side view of the anvil retainer shown in FIG. 7A;

FIG. 7C is a cross-sectional view taken along section lines 7C-7C ofFIG. 7B;

FIG. 8 is a side perspective view of the screw and screw stop of theapproximation mechanism of the handle assembly shown in FIG. 5;

FIG. 9 is an enlarged view of the indicated area of detail shown in FIG.3;

FIG. 9A is a side perspective view from the top of the abutment memberof the handle assembly shown in FIG. 3;

FIG. 10 is a side perspective exploded view from the proximal end of theanvil assembly of the surgical stapling device shown in FIG. 1;

FIG. 10A is a side perspective exploded view of another embodiment ofthe anvil assembly;

FIG. 10B is a side perspective view from the distal end of the retainermember of the anvil assembly shown in FIG. 10A;

FIG. 10C is a side cross-sectional view of the anvil assembly shown inFIG. 10A with the anvil head in the operative position prior todeformation of the retainer member;

FIG. 10D is an enlarged view of the indicated area of detail shown inFIG. 10C;

FIG. 10E is a side cross-sectional view of the anvil assembly shown inFIG. 10A with the anvil head in the operative position after deformationof the retainer member;

FIG. 10F is an enlarged view of the indicated area of detail shown inFIG. 10E;

FIG. 11 is a side perspective view of the retaining clip of the anvilassembly shown in FIG. 10;

FIG. 12 is a side perspective view of the distal end of the center rodof the anvil assembly shown in FIG. 10 with a removable trocar fastenedthereto;

FIG. 13 is a side perspective view of the center rod and removabletrocar shown in FIG. 11 separated one from the other;

FIG. 14 is a side perspective view from the proximal end of the anvilassembly shown in FIG. 10 with the removable trocar attached thereto;

FIG. 15 is a side perspective view from the distal end of the anvilassembly shown in FIG. 14;

FIG. 16 is a side cross-sectional view taken through the retaining clipof the anvil assembly and removable trocar of the anvil assembly shownin FIG. 15;

FIG. 16A is a side view of an alternate embodiment of the anvil assemblyshown in FIG. 14;

FIG. 16B is a side cross-sectional view of the anvil assembly shown inFIG. 16A taken through the retaining clip;

FIG. 17 is an enlarged view of the indicated area of detail shown inFIG. 16;

FIG. 18 is a side cross-sectional view taken through the pivot member ofthe anvil head assembly of the anvil assembly shown in FIG. 15;

FIG. 19 is a side perspective view from the proximal end of the anvilassembly shown in FIG. 18 with the removable trocar removed;

FIG. 20 is a perspective, partial cutaway view from the distal end ofthe anvil assembly shown in FIG. 19, with the anvil head removed;

FIG. 21 is a side cross-sectional partial cutaway view of the distalportion of the anvil assembly shown in FIG. 19, with the anvil headshown in phantom;

FIG. 22 is a side perspective view from the bottom of the screw stop ofthe handle assembly shown in FIG. 3;

FIG. 23 is a bottom perspective view from the proximal end of the screwstop shown in FIG. 22;

FIG. 24 is a top perspective view of the cam adjustment member of thehandle assembly shown in FIG. 3;

FIG. 25 is a side view of the screw and screw stop of the handleassembly shown in FIG. 3 with the set screw and the cam adjustmentmember removed;

FIG. 26 is a side view of the screw and screw stop shown in FIG. 25 withthe set screw and cam adjustment member attached thereto;

FIG. 27 is a side view of the screw and screw stop shown in FIG. 26 withthe cam adjustment screw adjusted to increase the tissue gap;

FIG. 28 is a side view of the screw and screw stop shown in FIG. 26 withthe cam adjustment screw adjusted to decrease the tissue gap;

FIG. 29 is a top perspective view from the proximal end of the slidemember of the indicator mechanism of the handle assembly shown in FIG.3;

FIG. 30 is a bottom perspective view of the lockout member of the firelockout mechanism of the handle assembly shown in FIG. 3;

FIG. 31 is a side cross-sectional view of the surgical stapling deviceshown in FIG. 1 with the anvil assembly removed;

FIG. 32 is a side enlarged view of the handle assembly of the surgicalstapling device shown in FIG. 31 with the handle sections removed;

FIG. 33 is an enlarged view of the indicated area of detail shown inFIG. 31;

FIG. 34 is an enlarged view of the indicated area of detail shown inFIG. 31;

FIG. 35 is a perspective view from the front of the distal end of thesurgical stapling device shown in FIG. 31 with the anvil assemblyremoved;

FIG. 36 is a perspective view from the front of the distal end of thesurgical stapling device shown in FIG. 35 with an anvil assemblyattached thereto;

FIG. 37 is a side cross-sectional view of the distal end of the surgicalstapling device shown in FIG. 36;

FIG. 38 is a side cross-sectional view of the surgical stapling deviceshown in FIG. 31 with the anvil assembly attached thereto;

FIG. 39 is a cross-sectional view taken along section lines 39-39 ofFIG. 38;

FIG. 40 is a cross-sectional view taken along section lines 40-40 ofFIG. 38;

FIG. 41 is a cross-sectional view taken along section lines 41-41 ofFIG. 38;

FIG. 42 is a cross-sectional view taken along section lines 42-42 ofFIG. 38;

FIG. 43 is a cross-sectional view taken along section lines 43-43 ofFIG. 38;

FIG. 44 is a cross-sectional view taken along section lines 44-44 ofFIG. 38;

FIG. 45 is a side perspective view of the surgical stapling device shownin FIG. 38 with the anvil assembly in an approximated position;

FIG. 46 is a side cross-sectional view of the distal end of the surgicalstapling device shown in FIG. 45;

FIG. 47 is a side enlarged view of the handle assembly of the surgicalstapling device shown in FIG. 45 with a handle section removed;

FIG. 48 is a side cross-sectional view of the handle assembly of thesurgical stapling device shown in FIG. 45;

FIG. 49 is a top horizontal cross-sectional view of a portion of thehandle assembly of the surgical stapling device shown in FIG. 45;

FIG. 50 is a side view of a portion of the handle assembly of thesurgical stapler shown in FIG. 45 with the handle sections removed;

FIG. 51 is a side cross-sectional view of a portion of the handleassembly of the surgical stapling device shown in FIG. 45 after thefiring trigger has been actuated;

FIG. 52 is a side cross-sectional view of the distal end of the surgicalstapling device shown in FIG. 45 after the firing trigger has beenactuated;

FIG. 53 is a side view of the handle assembly shown in FIG. 51 with thehandle sections removed;

FIG. 54 is an enlarged view of the firing link extension engaging theabutment member of the tactile indicator mechanism of the handleassembly shown in FIG. 53;

FIG. 55 is a side cross-sectional view of the distal portion of theanvil assembly of the surgical stapling device shown in FIG. 52;

FIG. 56 is a side cross-sectional view of the distal portion of theanvil assembly shown in FIG. 55 with a portion of the anvil headassembly in phantom;

FIG. 57 is a side view of the surgical stapling device shown in FIG. 45after the anvil assembly and cartridge assembly have been unapproximateda distance sufficient to permit the anvil head assembly to pivot on theanvil center rod;

FIG. 58 is an enlarged view of the abutment member of the tactileindicator mechanism of the handle assembly shown in FIG. 53 (duringunapproximation of the anvil and cartridge assemblies) with the wing ofthe screw stop, shown in phantom, in engagement with the abutmentmember;

FIG. 59 is a side cross-sectional view of the anvil assembly shown inFIG. 56 as the anvil head assembly begins to tilt;

FIG. 60 is a side cross-sectional view of the anvil assembly shown inFIG. 59 with the anvil assembly tilted;

FIG. 61 is a side view of the surgical stapling device shown in FIG. 45with the anvil head assembly unapproximated and tilted.

FIG. 62 is a side perspective view from the distal end of an alternateembodiment of the presently disclosed surgical stapling device with theanvil assembly removed from the device;

FIG. 63 is a side perspective view from the proximal end of anotherembodiment of the anvil assembly for use with the surgical staplingdevice shown in FIG. 62;

FIG. 64 is a side cross-sectional view of the anvil assembly shown inFIG. 63;

FIG. 64A is a side view of another embodiment of the anvil assemblyshown in FIG. 63;

FIG. 64B is a side cross-sectional view of the anvil assembly shown inFIG. 64A;

FIG. 65 is a side exploded perspective view of the anvil assembly shownin FIG. 63;

FIG. 66 is a side exploded perspective view of the distal head portion,anvil retainer assembly and pusher back of the surgical stapling deviceshown in FIG. 62;

FIG. 66A is a side perspective view from the proximal end of anotherembodiment of the anvil retainer assembly shown in FIG. 66;

FIG. 66B is a side exploded perspective view from the distal end of theanvil retainer assembly shown in FIG. 66A;

FIG. 67 is a side cross-sectional view of the distal end of the centralbody portion and distal head portion of the surgical stapling deviceshown in FIG. 62 with the anvil assembly removed;

FIG. 68 is side cross-sectional view of the distal end of the centralbody portion and distal head portion shown in FIG. 67 with the anvilassembly shown in FIG. 63 secured to the anvil retainer assembly, theanvil assembly in its unapproximated position and the anvil head in theoperative position;

FIG. 69 is a cross-sectional view of the distal end of the central bodyportion and distal head portion shown in FIG. 68 taken along sectionlines ninety-degrees offset from the section lines of FIG. 68;

FIG. 70 is a cross-sectional view of the distal end of the central bodyportion and distal head portion shown in FIG. 68 with the anvil headmoved to the approximated position;

FIG. 71 is a cross-sectional view of the distal end of the central bodyportion and distal head portion shown in FIG. 69 with the anvil headmoved to the approximated position;

FIG. 72 is a cross-sectional view of the distal end of the central bodyportion and distal head portion shown in FIG. 70 after the staplingdevice has been fired;

FIG. 73 is a cross-sectional view of the distal end of the central bodyportion and distal head portion shown in FIG. 71 after the staplingdevice has been fired;

FIG. 74 is a cross-sectional view of the distal end of the central bodyportion and distal head portion shown in FIG. 73 after the anvil headhas been unapproximated and pivoted to the tilted position;

FIG. 74A is a side cross-sectional view of an anvil adaptor suitable foruse during a gastric bypass procedure;

FIG. 75 is a side perspective view from the proximal end of anotherembodiment of the surgical stapling device with the anvil head in itsunapproximated position;

FIG. 76 is a side perspective view from the proximal end of the handleassembly of the stapling device shown in FIG. 75;

FIG. 77 is an enlarged view of the indicated area of detail shown inFIG. 75;

FIG. 78 is an enlarged view of the indicated area of detail shown inFIG. 76;

FIG. 79 is an exploded side perspective view of the handlehalf-sections, trigger lock and passive lockout mechanism of thestapling device shown in FIG. 75;

FIG. 80 is a side perspective view from the proximal end of the screwstop of the surgical stapling device shown in FIG. 75;

FIG. 81 is a side perspective view of the interlock plate of thesurgical stapling device shown in FIG. 75;

FIG. 82 is a side perspective view of the trigger lock of the surgicalstapling device shown in FIG. 75;

FIG. 83 is a side view of the surgical stapling device shown in FIG. 75with a handle half-section removed and the anvil head in itsapproximated position;

FIG. 84 is an enlarged view of the indicated area of detail shown inFIG. 83;

FIG. 85 is a side view of the handle assembly of the surgical staplingdevice shown in FIG. 83 with a handle half-section removed;

FIG. 86 is a side perspective view from the proximal end of the handleassembly shown in FIG. 85;

FIG. 87 is a side view of the surgical stapling device shown in FIG. 83with a handle half-section removed, the anvil head in an approximatedposition, and the trigger lock moved to its unlocked position;

FIG. 88 is an enlarged view of the indicated area of detail shown inFIG. 87;

FIG. 89 is a side view of the handle assembly of the surgical staplingdevice shown in FIG. 87 with a handle half-section removed and thetrigger lock in its unlocked position;

FIG. 90 is a side perspective view from the proximal end of the handleassembly shown in FIG. 89;

FIG. 91 is a side view of the surgical stapling device shown in FIG. 87with a handle half-section removed and the firing trigger actuated;

FIG. 92 is an enlarged view of the indicated area of detail shown inFIG. 91;

FIG. 93 is a side view of the handle assembly of the surgical staplingdevice shown in FIG. 91 with a handle half-section removed and thefiring trigger actuated;

FIG. 94 is a side perspective view from the proximal end of the handleassembly shown in FIG. 93;

FIG. 95 is a side view of the handle assembly of another embodiment ofthe presently disclosed surgical stapling device; and

FIG. 96 is a bottom view of the handle assembly shown in FIG. 95.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Embodiments of the presently disclosed surgical stapling device will nowbe described in detail with reference to the drawings in which likereference numerals designate identical or corresponding elements in eachof the several views.

Throughout this description, the term “proximal” will refer to theportion of the instrument closest to the operator and the term “distal”will refer to the portion of the instrument furthest from the operator.

FIGS. 1 and 2 illustrate one embodiment of the presently disclosedsurgical stapling device shown generally as 10. Briefly, surgicalstapling device 10 includes a proximal handle assembly 12, an elongatedcentral body portion 14 including a curved elongated outer tube 14 a,and a distal head portion 16. Alternately, in some surgical procedures,e.g., the treatment of hemorrhoids, it is desirable to have asubstantially straight, shortened, central body portion. The length,shape and/or the diameter of body portion 14 and head portion 16 mayalso be varied to suit a particular surgical procedure.

Handle assembly 12 includes a stationary handle 18, a firing trigger 20,a rotatable approximation knob 22 and an indicator 24. In oneembodiment, stationary handle 18 is formed from thermoplastic handlesections 18 a and 18 b, e.g., polycarbonate, (FIG. 3) which togetherdefine a housing for the internal components of handle assembly 12.Handle sections 18 a and 18 b can be secured together by sonic welding.Alternately, other known securement techniques may be employed includingscrews, adhesives, snap-fit connectors, etc. The internal components ofhandle portion 12 will be discussed in detail below. In one embodiment,cushioned and/or resilient slip resistant portions such as a grip (notshown) can be fastened to or included as part of handle sections 18 aand 18 b and firing trigger 20. The slip resistant grip may be formedover handle sections 18 a and 18 b and firing trigger 20 using anovermolding procedure and may be formed from neoprene or rubber.Alternately, other suitable materials, e.g., elastomeric materials, andjoining techniques may be employed. A pivotally mounted trigger lock 26is fastened to handle assembly 12 and is manually positioned to preventinadvertent firing of stapling device 10. Indicator 24 is positioned onthe stationary handle 18 and includes indicia, e.g., color coding,alpha-numeric labeling, etc., to identify to a surgeon whether thedevice is approximated and is ready to be fired. In one embodiment,indicator 24 has a bulbous or convex shape which extends outwardly froma top surface of handle sections 18 a and 18 b and is easily viewable bya surgeon from the top and sides of the stapling device. A magnificationlens may be positioned over indicator 24 to further improvevisualization of the indicia.

Head portion 16 includes an anvil assembly 30 and a shell assembly 31.Each of these assemblies will be discussed in detail below. Except whereotherwise noted, the components of surgical device 10 are generallyformed from thermoplastics including polycarbonates, and metalsincluding stainless steel and aluminum. The particular material selectedto form a particular component will depend upon the strengthrequirements of the particular component. For example, the anvil may beformed from a metal, such as stainless steel, and the stationary handlemay be formed from a thermoplastic such as polycarbonate. Alternately,other materials not listed above, which can withstand sterilizationprocedures, may be used to form components of stapling device 10provided the materials are suitable for surgical use and meet thestrength requirements of the particular component.

FIGS. 3-5 illustrate the internal components of handle assembly 12. Theinternal components include the proximal components of approximation andfiring mechanisms, a firing lockout mechanism and an indicator drivemechanism. FIGS. 6 and 7 illustrate the internal components of elongatedbody portion 14. These components include the distal components of theapproximation and firing mechanisms. Each of these mechanisms will bedisclosed in detail hereinbelow.

Approximation Mechanism

Referring to FIGS. 3-8, the approximation mechanism includesapproximation knob 22, a drive screw 32, a rotatable sleeve 33, firstand second screw extensions 34 and 36 (FIG. 6), respectively, and ananvil retainer 38. Rotatable sleeve 33 includes a substantiallycylindrical hollow body portion 40 and a substantially cylindricalcollar 42 which together define a central bore 33 a. Collar 42 has anannular groove 44 formed thereabout which is dimensioned to receive aninwardly extending flange 46 formed on an inner wall of handle sections18 a and 18 b. Engagement between groove 44 and flanges 46 axially fixessleeve 33 within handle 18 while permitting rotation of sleeve 33 inrelation to stationary handle 18. The proximal end of body portion 40 ofrotatable sleeve 33 extends through an opening 18 b in the proximal endof stationary handle 18. A pair of diametrically opposed elongated ribs48 are positioned or formed on the outer surface of body portion 40.Approximation knob 22 includes a pair of internal slots 49 a positionedto receive ribs 48 of sleeve 33 to rotatably fix sleeve 33 to knob 22,such that rotation of knob 22 causes concurrent rotation of sleeve 33.

The proximal portion of screw 32 includes a helical channel 50 and isdimensioned to be slidably positioned within central bore 33 a ofrotatable sleeve 33. The distal end of screw 32 includes an annularrecess 35 dimensioned to receive a seal member 37 (FIG. 3) for providinga fluid tight seal between the outer surface of screw 32 and the innersurface of pusher link 74. A pin 52 (FIG. 3) extends radially throughcylindrical collar 42 of sleeve 33 into helical channel 50. Since sleeve33 is axially fixed with respect to stationary handle 18, rotation ofsleeve 33 about screw 32 causes pin 52 to move along channel 50 of screw32 to effect axial movement of screw 32 within stationary handle 18.

Referring to FIGS. 6-8, the distal end of screw 32 includes a transverseslot 54. Top and bottom screw extensions 34 and 36 (FIG. 6) each includea proximally located flexible flat band portion 58 and a distallylocated flat band portion 60. Alternately, it is envisioned that screwextensions 34 and 36 may have other than a band configuration. Forexample, screw extensions 34 and 36 may be semi-circular or circular incross-section. The flexibility of top and bottom screw extensions 34 and36 permits movement of screw extensions 34 and 36 through curvedelongated body portion 14. The proximal end of each band portion 58includes a hole 62 dimensioned to receive a pin 64 for securing theproximal end of screw extensions 34 and 36 within transverse slot 54 ofscrew 32. Alternately, other fastening techniques may be used to secureeach band portion 58 to screw 32, e.g., welding, crimping, etc. Distallylocated band portion 60 of each screw extension 34 and 36 is dimensionedto be received within a transverse slot 66 formed in a proximal end ofanvil retainer 38 (FIG. 7) to fasten anvil retainer 38 to the distal endof screw extensions 34 and 36. In one embodiment, a pair of pins 66 awhich extend through the proximal end of anvil retainer 38 and bandportions 60 are used to secure screw extensions 34 and 36 to anvilretainer 38. Alternately, band portions 60 can be brazed or weldedwithin slot 66 or other fastening techniques may be used to secure bandportions 60 of screw extensions 34 and 36 to anvil retainer 38, e.g.,screws, crimping, etc.

Anvil retainer 38 includes a trocar portion 38 a, a body portion 38 band an attachment portion 38 c. Trocar portion 38 a includes a blunttrocar tip 39. Body portion 38 b is substantially cylindrical and has adiameter which is larger than the diameter of trocar portion 38 a. Anannular protrusion 177 (FIG. 7) which is configured to engage the anvilassembly in a manner to be discussed in detail below is positioned aboutbody portion 38 b of anvil retainer 38 at a location spaced from trocarportion 38 a.

FIGS. 7A-7C illustrate an alternate embodiment of anvil retainer 38shown generally as 38′. Anvil retainer 38′ includes a trocar portion38′a, a body portion 38′b and an attachment portion 38′c. Attachmentportion 38′c is substantially the same as attachment portion 38 c aboveand will not be discussed in further detail. Trocar portion 38′ includesa blunt trocar tip 39′. A protrusion 177′ is formed about body portion38′b at a location spaced proximally of trocar portion 38 a tofacilitate engagement with an anvil assembly. Body portion 38′b betweentrocar portion 38′a and protrusion 177′ defines a smooth concavity orcoke-bottle shape. The shape permits tissue to slide over the anvilretainer prior to attachment to an anvil assembly. Alternately,protrusion 177 need not be annular or may include different attachmentstructure, e.g., recesses, grooves, etc.

Referring again to FIGS. 3-7, when approximation knob 22 is manuallyrotated, rotatable sleeve 33 is rotated about the proximal end of screw32 to move pin 52 along helical channel 50 of screw 32. Since sleeve 33is axially fixed to stationary handle 18, as pin 52 is moved throughchannel 50, screw 32 is advanced or retracted within stationary handle18. As a result, top and bottom screw extensions 34 and 36, which arefastened to the distal end of screw 32, and anvil retainer 38, which isfastened to the distal end of screw extensions 34 and 36, are movedaxially within elongated body portion 14. Since anvil assembly 30 issecured to the distal end of anvil retainer 38, rotation ofapproximation knob 22 will effect movement of anvil assembly 30 inrelation to shell assembly 31 between spaced and approximated positions.

Firing Mechanism

Referring to FIGS. 3-6 and 9, the firing mechanism includes firingtrigger 20, a firing link 72 and an elongated pusher link 74 (FIG. 6).Firing trigger 20 includes a body portion 76 and a trigger cover 80. Acushioned gripping surface (not shown) which may be formed of neopreneor rubber may be provided on trigger cover 80. The cushioned grippingsurface provides a non-slip and/or cushioned surface to make actuationof device 10 more comfortable to a surgeon. The distal end of bodyportion 76 of trigger 20 is pivotally connected to a coupling member 86by a pivot member 84. Coupling member 86 is secured to the proximal endof pusher link 74 and may be formed integrally with pusher link 74 or asa separate element fastened thereto. Firing link 72 has a distal endpivotally secured to body portion 76 of trigger 20 by a pivot member 87and a second end pivotally secured within a vertical slot 82 formedbetween stationary handle half-sections 18 a and 18 b of stationaryhandle 18 by pivot member 79. Pivot member 79 is free to move verticallywithin slot 82. A spring 82 a (FIG. 9) is supported within handle 18 tourge pivot member 79 downwardly towards the bottom of slot 82. Bodyportion 76 of trigger 20 further includes a pair of abutments includingan abutment 89 and an abutment 91 which are positioned to engage thedistal end 26 a (FIG. 4) of trigger lock 26 in a manner to be describedin greater detail below to prevent actuation of trigger 20 prior toapproximation of device 10.

Coupling member 86 which is supported on the proximal end of elongatedpusher link 74 includes a flange 104 (FIG. 6). A spring 106 ispositioned between a proximal end 15 of outer tube 14 a and flange 104(FIG. 4) to bias pusher link 74 proximally to a retracted, non-firedposition. A pair of wings 108 extend radially outwardly from couplingmember 86. Wings 108 are dimensioned to slide along channels 111 (FIG.3) formed along the internal walls of stationary handle 18 to maintainproper alignment of pusher link 74 within stationary handle 18 duringfiring of device 10.

Referring to FIG. 6, the distal end of pusher link 74 includes a pair ofengagement fingers 110 which are dimensioned to lockingly engage withmembers 220 formed in the proximal end of pusher back 186. Pusher back186 forms part of shell assembly 31 and will be discussed in greaterdetail below. Pusher link 74 can be formed from a flexible plasticmaterial and includes a plurality of notches 187 which allow the pusherlink to bend more easily as it moves through body 14. Pusher link 74defines a hollow channel 75 for slidably receiving the approximationmechanism. A flat surface or cutout 74 a (FIG. 6) is formed in bothsides of pusher link 74 and on one side slidably supports screwextensions 34 and 36 which are positioned in juxtaposed alignment.Spacers 77 are positioned within outer tube 14 a adjacent cutout 74 a toprovide additional support for screw extensions 34 and 36 and pusherlink 74 to prevent each component from buckling during actuation. Anannular channel 74 b is formed about pusher link 74 to receive an O-ringseal 74 c. Pusher link 74 is slidably positioned within body portion 14such that O-ring 74 c seals the space between pusher link 74 and aninternal wall of outer tube 14 a. Operation of the firing mechanism ofthe device will be described in detail below.

Referring again to FIGS. 3-6 and 9, when firing trigger 20 is actuated,i.e., pivoted about pivot member 84, firing link 72 is moved proximallyuntil pivot member 79 engages an abutment surface 307 (FIG. 25A-D)formed on screw stop 306 (FIG. 3). Screw stop 306 is axially fixed toscrew 32 in a manner to be described in detail below. Thereafter, firingtrigger 20 is pushed distally to advance pusher link 74 distally againstthe bias of spring 106. Since the distal end of pusher link 74 isconnected to pusher back 186, actuation of firing trigger 20 effectsadvancement of pusher back 186 within shell assembly 31 to eject staplesfrom shell assembly 31 in a manner to be described below.

Anvil Assembly

Referring to FIGS. 10-21, anvil assembly 30 includes an anvil headassembly 120 and an anvil center rod assembly 152. Anvil head assembly120 includes a post 122, an anvil head 124, a backup plate 126, acutting ring 128, a retaining clip 127 and an anvil 129. Post 122 iscentrally positioned through a bore in anvil head 124. Alternately, post122 may be integrally formed with anvil head 124. Anvil 129 is supportedon anvil head 124 in an outer annular recess 136 and includes aplurality of pockets 140 for receiving and deforming staples. At leastone tab 129 a extends radially outwardly from anvil 129 and isdimensioned to be received within a cutout 124 a formed in anvil head124. Tab 129 a and cutout 124 a function to align anvil 129 withinannular recess 136.

Backup plate 126 includes a central opening 126 b which is positionedabout post 122 within an inner recess 134 of anvil head 124 between post122 and annular recess 136. Backup plate 126 includes a raised platform126 a. Cutting ring 128 includes an opening 128 a having a configurationsubstantially the same as platform 126 a. Although platform 126 a isillustrated as having a circular shape, other platform configurationsare envisioned. Alternately, a platform need not be provided. In oneembodiment, cutting ring 128 is formed from polyethylene and is fixedlysecured to backup plate 126 using, for example, an adhesive. Backup ring126 can be formed from metal and provides support to cutting ring 128 toenhance the cutting of tissue. Alternately other materials ofconstruction may be used to construct plate 126 and ring 128. Cuttingring 128 and backup plate 126 are slidably mounted about post 122.Backup plate 126 includes a pair of inwardly extending tabs 150 whichwill be described in further detail below.

Anvil center rod assembly 152 includes anvil center rod 154, a plunger156 and plunger spring 158. A first end of center-rod 154 includes atransverse throughbore 160 which is offset from the central longitudinalaxis of center rod 154. Post 122 of anvil head assembly 120 alsoincludes a transverse throughbore 162. A pivot member 164 pivotablysecures post 122 to center rod 154 such that anvil head assembly 120 ispivotably mounted to anvil center rod assembly 152. Plunger 156 isslidably positioned in a bore 154 b (FIG. 16) formed in the first end ofcenter rod 154. Plunger 156 includes an engagement finger 168 which isoffset from the pivot axis of anvil head assembly 120 and biased intoengagement with base 122 a of post 122 by plunger spring 158 to urgeanvil head assembly 120 to a pivoted position at an angle to center rod154. In a prefired untilted position, tabs 150 formed on backup plate126 engage a top surface 154 a (FIG. 20) of center rod 154 to preventanvil head assembly 120 from pivoting about pivot member 164. As device10 is fired, backup plate 126 and cutting ring 128 are moved or slidedeeper into anvil recess 134 of anvil head 124 about post 122 (FIG. 21)by knife 188 (FIG. 6) in a manner to be described in further detailbelow to move tabs 150 out of engagement with top surface 154 a ofcenter rod 154 to permit plunger 156 to pivot anvil head assembly 120about pivot member 164.

Referring to FIGS. 10A-F, in an alternate embodiment of the anvilassembly shown generally as 30′ a retainer member 131 is positioned ininner annular recess 134 between backup plate 126 and a back wall ofanvil head 124. In one embodiment, retainer member 131 is annular andincludes a plurality of deformable tabs 131 a which engage a rearsurface of backup plate 126. Retainer member 131 prevents backup plate126 and cutting ring 128 from moving into annular recess 134 of anvilhead 124 until a predetermined force sufficient to deform tabs 131 a hasbeen applied to the backup member. The predetermined force sufficient todeform tabs 131 a has been applied to the backup member. Thepredetermined force can be close to but is less than the force appliedby an annular cutting blade of a surgical stapling device when itengages the backup member of the anvil assembly device. In oneembodiment, the predetermined force is between about ten pounds andabout ninety pounds and can be about fifty pounds. When thepredetermined force is reached, e.g., during cutting of tissue, backupplate 126 will move from a first position to a second position withininner annular recess 134 of anvil head 124 and compress retainer member131. It is envisioned that other crushable, deformable, collapsible ormovement restricting members may be used to retain the backup member ina fixed position until the predetermined force has been applied to thebackup member.

A retainer clip 127 is positioned in a transverse slot 122 c formed inpost 122 and includes a pair of outwardly biased flexible arms 127 a and127 b. Arm 127 b includes a recess 127 c dimensioned to receive pivotpin 164 (FIG. 17). Prior to firing device 10, arms 127 a and 127 b aredeformed inwardly by backup plate 126 (FIG. 17). After device 10 hasbeen fired and backup plate 126 has been pushed deeper into anvil head124 by knife 188, flexible arms 127 a and 127 b spring outwardly to aposition in front of backup plate 126. In this position, arms 127 a and127 b prevent cutting ring 128 and backup plate 126 from sticking toknife 188 when anvil assembly 30 is unapproximated. It is envisionedthat a retainer clip may be used in conjunction with non-pivotal anvilassemblies wherein the anvil head post and the anvil center rod areintegrally formed.

A second end of center rod 154 includes a bore 170 defined by aplurality of flexible arms 155. Bore 170 is dimensioned to receive aremovable trocar 157. At least one of flexible arms 155, and in oneembodiment, a plurality of flexible arms 155, e.g., three, include anopening 155 a dimensioned to receive a projection 157 d formed onremovable trocar 157 to releasably secure trocar 157 to center rod 154(FIG. 13). The distal ends of each of flexible arms 155 include aninternal shoulder 155 b (FIG. 10) dimensioned to releasably engage anvilretainer 38 in a manner to be discussed in detail below. A plurality ofsplines 181 are formed about center rod 154 and are dimensioned to bereceived within grooves 196 a (FIG. 6) in shell assembly 31 to alignanvil assembly 30 within shell assembly 31 during approximation of theanvil and shell assemblies. Center rod 154 also includes an annularrecessed portion 183 to facilitate grasping of anvil assembly 30 by asurgeon with a grasper.

Referring to FIGS. 12 and 13, removable trocar 157 includes a trocar tip157 a, a body portion 157 b and a cantilevered arm 157 c. A projection157 d is positioned on the free end of cantilevered arm 157 c. Arm 157 cis deflectable downwardly, i.e., radially inwardly, in the directionindicated by arrow “A” in FIG. 13, to facilitate insertion of bodyportion 157 b into bore 170 of center rod 154. Splines 157 e or thelike, are provided on body portion 157 b to properly align trocar 157within bore 170. Arm 157 c biases projection 157 d outwardly such thatwhen projection 157 d passes beneath opening 155 a in center rod 154,projection 157 d snaps outwardly into opening 155 a to releasably secureremovable trocar 157 to center rod 154. A tab 157 f is positioned on arm157 c and can be engaged to depress arm 157 c and projection 157 d toremove projection 157 d from an opening 155 a of arm 155 to facilitateremoval of trocar 157 from center rod 154. Trocar tip 157 a includes athroughbore 157 g dimensioned to receive a suture (not shown) tofacilitate locating and removal of trocar 157 and/or anvil assembly 30within and from the human body. Although illustrated as having asharpened tip, other trocar tip configurations are envisioned, e.g., ablunt tip.

Shell Assembly

Referring to FIG. 6, shell assembly 31 includes a shell 182, a pusherback 186, a cylindrical knife 188, and a staple guide 192. Shell 182includes an outer housing portion 194 and an inner guide portion 196having grooves 196 a for mating with splines 181 on anvil center rod 154(FIG. 10). Outer housing portion 194 defines a throughbore 198 having adistal cylindrical section 200, a central conical section 202 and aproximal smaller diameter cylindrical section 204. A plurality ofopenings 206 are formed in conical section 202. Openings 206 aredimensioned to permit fluid and tissue passage during operation of thedevice. A pair of diametrically opposed flexible engagement members 207are formed on proximal cylindrical section 204 of shell 182. Engagementmembers 207 are positioned to be received in openings 207 a formed onthe distal end of outer tube 14 a to secure shell 182 to elongated body14. A pair of openings 211 formed in the proximal end of outer tube 14 aare dimensioned to receive protrusions (not shown) formed on theinternal wall of stationary handle 18 to facilitate attachment of tube14 a to handle portion 12.

Pusher back 186 includes a central throughbore 208 which is slidablypositioned about inner guide portion 196 of shell 182. Pusher back 186includes a distal cylindrical section 210 which is slidably positionedwithin distal cylindrical section 200 of shell 182, a central conicalsection 212 and a proximal smaller diameter cylindrical section 214. Theproximal end of pusher back 186 includes members 220 which areconfigured to lockingly engage with resilient fingers 110 of pusher link74 to fasten pusher link 74 to pusher back 186 such that a distal faceof pusher link 74 abuts a proximal face of pusher back 186.

The distal end of pusher back 186 includes a pusher 190. Pusher 190includes a multiplicity of distally extending fingers 226 dimensioned tobe slidably received within slots 228 formed in staple guide 192 toeject staples 230 therefrom. Cylindrical knife 188 is frictionallyretained within the central throughbore of pusher back 186 to fixedlysecure knife 188 in relation to pusher 190. Alternately, knife 188 maybe retained within pusher back 186 using adhesives, crimping, pins, etc.The distal end of knife 188 includes a circular cutting edge 234.

In operation, when pusher link 74 is advanced distally in response toactuation of firing trigger 20, as will be described below, pusher back186 is advanced distally within shell 182. Advancement of pusher back186 advances fingers 226 through slots 228 of staple guide 192 toadvance staples 230 positioned within slots 228 and eject staples 230from staple guide 192 into staple deforming pockets 140 of anvil 129.Since knife 188 is secured to pusher back 186, knife 188 is alsoadvanced distally to core tissue as will be described in more detailbelow.

A rigid bushing 209 is supported in the proximal end of inner guideportion 196 of shell 182. Bushing 209 defines a throughbore dimensionedto slidably receive anvil retainer 38 and center rod 154 of anvilassembly 30 (FIG. 14). Bushing 209 provides lateral support for flexiblearms 155 of center rod 154 when the anvil assembly 30 has beenapproximated to prevent disengagement of anvil assembly 30 from anvilretainer 38. In the unapproximated position, flexible arms 155 of centerrod 154 are positioned externally of bushing 209 to permit removal ofanvil assembly 30 from retainer 38.

Cam Adjustment Mechanism

Referring to FIGS. 8 and 22-28, a cam adjustment member 400 is securedby set screw 312 onto a sidewall 306 a of screw stop 306 within a recess306 b formed in sidewall 306 a. Cam adjustment member 400 includes acircular disc 402 having a throughbore 404. Throughbore 404 iseccentrically formed through disc 402 and is dimensioned to receive setscrew 312. A smaller notch or hole 406 is also formed in disc 402 and isdimensioned to receive the tip of an adjustment tool (not shown). Recess306 b (FIG. 22) includes a forward abutment shoulder or surface 306 cand a rear abutment surface 306 d and is dimensioned to receive disc 402such that the outer edge of disc 402 abuts forward and rear abutmentsurfaces 306 c and 306 d.

Set screw 312 extends through disc 402 and screw stop 306 and isreceived in a threaded bore 32 a (FIG. 6) in screw 32 to secure screwstop 306 in an axially fixed position on screw 32. Cam adjustment member400 functions to adjust the axial position of screw stop 306 on screw32. More specifically, set screw 312 can be loosened to allow disc 402to rotate within recess 306 b of screw stop 306. Since disc 402 iseccentrically mounted about screw 32 and engages forward and rearabutment surfaces 306 c and 306 d of recess 306 b, rotation of disc 402about fixed set screw 312 will urge screw stop 306 axially along screw32 to adjust the axial position of screw stop 306 on screw 32. Forexample, when disc 402 is rotated in a clockwise direction (as viewed inFIG. 28) as indicated by arrow “B”, screw stop 306 will be moved axiallyin relation to screw 32 in the direction indicated by arrow “C” inresponse to engagement between the outer edge of disc 402 and rearshoulder 306 d of recess 306 b. Conversely, when disc 402 is rotated ina counter-clockwise direction (as viewed in FIG. 27), as indicated byarrow “D”, screw stop 306 will be moved axially in relation to screw 32in the direction indicated by arrow “E” in response to engagementbetween the outer edge of disc 402 and forward shoulder 306 c of recess306 b.

When stapling device 10 is in a fully approximated position, i.e., anvilassembly 30 and shell assembly 31 are brought into juxtaposed alignmentto define a tissue receiving clearance (FIG. 46), screw stop 306 abutsagainst body portion 42 of the rotatable sleeve 33, i.e., sleeve 33functions as a proximal stop for the approximation mechanism. See FIG.48. In this position, anvil assembly 30 and shell assembly 31 are spacedslightly to define a tissue receiving clearance. By providing camadjustment member 400, the tissue receiving clearance can be selectivelyadjusted to be within a desired range by adjusting the position of screwstop 306 on screw 32. In one embodiment, cam adjustment member 400permits adjustment of the tissue receiving clearance of ±0.045 inches,although greater or lesser adjustment capabilities are also envisioned.Typically, adjustments to the tissue receiving clearance will be made bythe device manufacturer. Alternately, a hole or opening may be providedin handle portion 12 (FIG. 1) to provide direct access to adjustmentmember 400 to allow for on-site adjustment of the tissue receivingclearance by a surgeon or other medical professional.

Indicator Mechanism

Referring to FIGS. 3-5 and 29, the indicator mechanism includes bulbousindicator 24, lens cover 24 a and slide member 500. Indicator 24 ispivotally supported about a pivot member 502 which can be formedmonolithically with handle sections 18 a and 18 b. Lens cover 24 a ispositioned above indicator 24 and, in one embodiment, is formed ofmagnification material to facilitate easy visualization of indicator 24.Slide member 500 includes a body portion 504 having an elongated slot506 formed therein, a distal abutment member or upturned lip portion508, and a proximal extension 510. Slide member 500 is slidablypositioned between handle sections 18 a and 18 b. Proximal extension 510is slidably supported within stationary handle 18 by support structure516 (FIG. 5) which may be integrally formed with handle sections 18 aand 18 b. A biasing member, e.g., a coil spring 512, is positioned incompression about proximal extension 510 between support structure 516and body portion 504 of slide member 500 to urge slide member 500distally within stationary handle 18. Indicator 24 includes a pair ofdownwardly extending projections 518 and 520 (FIG. 32). Upturned lipportion 508 of slide member 500 is positioned between projections 518and 520 and is positioned to engage projections 518 and 520 as it moveswithin stationary handle 18. In the unfired position of device 10,biasing member 512 urges slide member 500 distally to move lip portion508 into engagement with projection 518 to pivot indicator 24 to a firstposition, which provides indication to a surgeon that the device has notbeen approximated and is not in a fire-ready condition.

As discussed above, screw stop 306 is fixedly attached to screw 32 (FIG.33). Screw stop 306 includes a first abutment or engagement member 522which is positioned to travel through slot 506 of slide member 500 andengage the proximal end 506 a (FIG. 29) of slot 506 during approximationof the device. When engagement member 522 abuts proximal end 506 a ofslot 506, further approximation of device 10 moves slide plate 500proximally within stationary handle 18 against the bias of spring 512such that upturned lip 508 of slide member 500 engages projection 520 ofindicator 24. Engagement between projection 520 and lip 508 causesindicator 24 to pivot about pivot member 502 to a second position. Inthe second position, indicator 24 provides indication to a surgeon thatthe device has been approximated and is now in a fire-ready position.See FIG. 48.

Fire-Lockout Mechanism

Referring to FIGS. 3-5, and 30, the firing-lockout mechanism includestrigger lock 26 and a lockout member 530. Trigger lock 26 is pivotallysupported within bores 532 (FIG. 3) in handle sections 18 a and 18 babout pivot member 534. In one embodiment, pivot member 534 is T-shapedand frictionally engages the inner wall of bores 532 to prevent freerotation of trigger lock 26. Alternately, other pivot memberconfigurations are envisioned, e.g., circular, square, etc. Tip 26 a oftrigger lock 26 is positioned between abutments 89 and 91 on bodyportion 76 of firing trigger 20 to prevent actuation of trigger 20 whentrigger lock 26 is in the locked position. Trigger lock 26 also includesa proximal extension 26 b which will be discussed in further detailbelow.

In an alternate embodiment shown in FIG. 3B, a boot 26′c is secured tothe end of trigger lock 26′ for positioning between abutments 89 and 91.Boot 26′c may be formed integrally with trigger lock 26′, or may beformed separately of an appropriate material such as rubber or plasticand overmolded or otherwise attached to trigger lock 26′. Boot 26′cfrictionally retains firing lock 26′ between abutments 89 and 91 toprevent trigger lock 26 from rattling back and forth between abutments89 and 91. Trigger lock 26 also includes a proximal extension 26 b whichwill be discussed in further detail below.

Lockout member 530 includes a body portion 536, a proximal extension538, a pair of front legs 540 a, a pair of rear legs 540 b, and anabutment member or downturned lip portion 542. Lockout member 530 isslidably positioned between first and second stops 544 and 546 (FIG. 5)formed on an internal wall of handle sections 18 a and 18 b. Stop 544 ispositioned to engage extension 538 rear legs 540 b and stop 546 ispositioned to engage front legs 540 a. It is also envisioned that asingle abutment member may be substituted for each pair of legs. Abiasing member 549, e.g., a coil spring, is positioned between stop 544and rear legs 540 b of body 536 about proximal extension 538 to urgelockout 530 to its distal-most position with legs 540 abutting stop 546.In this position, extension 26 b of trigger lock 26 is positionedbeneath lip portion 542 of lockout member 530 to prevent pivotalmovement of trigger lock 26 about pivot member 534, and thus, preventfiring of stapling device 10.

As discussed above, screw stop 306 is secured to screw 32. A secondengagement member or members 548 extend downwardly from screw stop 306(FIG. 23). When stapling device 10 is approximated and screw 32 is movedproximally within stationary handle 18, engagement member 548 abutsdistal legs 540 a (FIG. 47) of lockout member 530 to move lockout member530 proximally against the bias of spring member 549 to a position inwhich lip portion 542 is spaced proximally of extension 26 b of triggerlock 26. In this position of lockout member 530, trigger lock 526 can bepivoted about pivot member 534 to permit firing of stapling device 10.

Tactile Indicator Mechanism

Referring to FIGS. 3, 5, 9 and 9A, a tactile indicator mechanismprovided in stationary handle 18 includes an abutment member 580 whichis slidably positioned in a vertical slot 582 defined within handlesections 18 a and 18 b. Abutment member 580 includes a protuberance 580a and a guide rib 580 b. Protuberance 580 a is dimensioned to bereceived within one of two detents or recesses 582 a and 582 b formedalong a wall of slot 582. Abutment member 580 is movable from aretracted (downward) position, wherein protuberance 580 a is positionedwithin detent 582 a, to an extended (upward) position, whereinprotuberance 580 a is positioned within detent 582 b. Engagement betweenprotuberance 580 a and detents 582 a and 582 b retains abutment member580 in its respective upward or downward position.

Prior to firing of stapling device 10, abutment member 580 is located inthe retracted (downward) position. When device 10 is fired, an extension590 (FIG. 3) of firing link 72 engages abutment member 580 and movesabutment member 580 from its retracted to its extended position. In theextended position, abutment member 580 extends into channel 111 ofstationary handle 18.

Screw stop 306 includes a pair of wings 584 which are slidablypositioned in channel 111 of stationary handle 18. After stapling device10 has been fired, abutment member 580 is positioned within channel 111.During unapproximation of anvil assembly 30 and cartridge assembly 31, awing 584 of screw stop 306 will engage abutment member 580 and urgeabutment member 580 back to its retracted (downward) position.Engagement between abutment member 580 and wing 584 of screw stop 306provides a tactile and/or an audible indication to the surgeon that theanvil and cartridge assemblies 30 and 31 have been unapproximated apredetermined amount. In one embodiment, abutment member 580 ispositioned to engage wing 584 of screw stop 306 at the point when theanvil and cartridge assemblies have been separated a distance sufficientto allow the anvil head assembly to tilt. This con occurs whenapproximation knob 22 has been turned from about two to about two and ahalf rotations. Thus, engagement between abutment member 580 and wing584 of screw stop 306 provides a tactile and/or audible indication tothe surgeon that the anvil head assembly 120 has tilted and staplingdevice 10 can be removed from a patient.

Operation

Operation of surgical stapling device 10 will now be described in detailwith reference to FIGS. 31-61.

FIGS. 31-35 illustrate surgical stapling device 10 in the unapproximatedor open position prior to attachment of anvil assembly 30 to anvilretainer 38. In this position, biasing member 106 (FIG. 33) is engagedwith coupling 86 to urge pusher link 74 to its proximal-most position inwhich coupling 86 abuts screw-stop 306. Biasing member 512 is engagedwith slide member 500 of the indicator mechanism to position slidemember 500 in engagement with projection 518 of indicator 24 to pivotindicator 24 in a clockwise direction, as viewed in FIG. 33. Biasingmember 549 is engaged with body 536 of lockout member 530 to urgelockout member 530 to its distal-most position, wherein lip portion 542of lockout member 530 is positioned above extension 26 b of trigger lock26 to prevent movement of trigger lock 26 to the unlocked position.Biasing member 82 a is also engaged with pivot member 79 (FIG. 32) tourge pivot member 79 to the base of vertical slot 82 and tactileindicator 580 is in the retracted or downward position with protrusion580 a positioned with detent 582 a.

FIGS. 36-44 illustrate surgical stapling device 10 with anvil assembly30 attached to anvil retainer 38 and anvil assembly 30 in theunapproximated or open position in relation to shell assembly 1.Referring to FIGS. 37 and 38, during attachment of anvil assembly 30 toanvil retainer 38, anvil retainer 38 is positioned within bore 170 ofcenter rod 154 of anvil assembly 30. Flexible arms 155 deflect outwardlyto accommodate center rod 154. Center rod 154 is advanced onto anvilretainer 38 in the direction indicated by arrow “K” in FIG. 37 untilinternal shoulder 155 b of flexible arms 155 passes over annularprotrusion 177 formed on a central portion of anvil retainer 38. At thispoint, resilient legs 155 releasably engage the anvil retainer. Theposition of the remaining components of stapling device are not affectedby attachment of anvil assembly 30 to anvil retainer 38 and remain asdescribed above and shown in FIGS. 31-35.

FIGS. 45-50 illustrate surgical stapling device 10 during movement ofanvil assembly 30 and cartridge assembly 31 to the approximated orclosed position. As discussed above, anvil assembly 30 is moved to theapproximated or closed position by rotating rotation knob 22 in thedirection indicated by arrow “L” in FIG. 45. Rotation of knob 22 causescylindrical sleeve 33 to rotate to move pin 52 along helical channel 50of screw 32. See FIG. 48. Movement of pin 52 along helical channel 50causes screw 32 to translate proximally within sleeve 33. The distal endof screw 32 is connected to screw extensions 34 and 36 which arefastened at their distal ends to anvil retainer 38 (FIG. 46). As such,retraction of screw 32 within sleeve 33 is translated into proximalmovement of anvil retainer 38 and anvil assembly 30. It is noted thatwhen anvil assembly 30 is approximated, flexible legs 155 of center rod154 are drawn into bushing 209 to lock legs 155 onto anvil retainer 38.

Referring to FIGS. 47-49, screw stop 306 is axially fixed to screw 32 byset screw 312. Thus, as screw 32 is retracted within sleeve 33, screwstop 306 is moved from a distal position within stationary handle 18 toa proximal position. As screw stop 306 moves from the distal position tothe proximal position, first engagement member 522 formed on screw stop306 abuts proximal end 506 a of slot 506 of slide plate 500 (FIG. 29)and moves slide plate 500 proximally against the bias of spring 512. Asslide plate 500 moves proximally, lip 508 (FIG. 48) of slide plate 500engages projection 520 of indicator 24 to pivot indicator 24 in acounter-clockwise direction as viewed in FIG. 48.

Screw stop 306 also includes a second engagement member 548 (FIG. 47).As screw stop 306 is moved from the distal position to the proximalposition during approximation of anvil assembly 30, second engagementmember 548 engages distal legs 540 a of lockout member 530 to movelockout member 530 proximally to a position in which lip portion 542 isspaced proximally of extension 26 b of trigger lock 26. In thisposition, trigger lock 26 can be pivoted to an unlocked position topermit firing of stapling device 10.

Movement of screw stop 306 to its proximal-most position withinstationary handle 18 positions abutment surface 307 of screw stop 306 inposition to engage pivot member 79 of firing link 72. Abutment surface307 comprises a substantially concave surface which is positioned topartially capture and act as a backstop for pivot 79 during firing ofstapling device 10.

FIGS. 51-56 illustrate surgical stapling device 10 during the firingstroke of firing trigger 20. As trigger 20 is compressed towardsstationary handle 18 in the direction indicated by arrow “M” in FIG. 52,pivot member 79 engages abutment surface 307 on screw stop 306 andfiring trigger 20 is pushed distally. As discussed above, the distal endof firing trigger 22 is connected through coupling member 86 to theproximal end of pusher link 74. Accordingly, as firing trigger 20 ismoved distally, pusher link 74 is moved distally in the directionindicated by arrow “N” in FIG. 52 to effect advancement of pusher back186 within shell assembly 31 (FIG. 52). Fingers 190 of pusher back 186engage and eject staples 230 from staple guide 192.

Cylindrical knife 188 is moved concurrently with pusher back 186 suchthat knife 188 moves into engagement with cutting ring 128 and backupplate 126. As discussed above, cutting ring 128 can be formed frompolyethylene and backup plate 126 can be formed from metal. When knife188 engages cutting ring 128, it cuts into cutting ring 128 and pushesbackup plate 126 deeper into anvil head 124 to move tabs 150 (FIG. 56)from engagement with top surface 154 a of center rod 154 (FIG. 56).Anvil head 124 is now free to pivot about member 164 and is urged to doso by plunger 156. It is noted that because the anvil assembly is injuxtaposed alignment with shell assembly 31, the anvil head 14 will notpivot fully until the anvil and shell assemblies have beenunapproximated a distance sufficient to allow the anvil head to fullypivot. When backup plate 126 moves into anvil head 124, flexible arms127 a and 127 b of retainer clip 127 (FIG. 55) spring outwardly to aposition in front of backup plate 126 blocking movement of backup plate126 out of anvil head 124. As discussed above, arms 127 a and 127 bprevent backup plate 126 from sticking to knife 188 when anvil assembly30 is returned to the unapproximated position.

Referring to FIGS. 53 and 54, as trigger 20 is actuated, i.e.,compressed towards stationary handle 18, extension 590 of firing link 72is pivoted towards and engages abutment member 580 to move abutmentmember 580 from its retracted to its extended position. In its extendedposition, abutment member 580 obstructs channel 111 of stationary handle18.

Referring to FIGS. 57-60, during unapproximation of stapling device 10after device 10 has been fired, wing 584 of screw stop 306 engagesabutment member 580 of the tactile indicator mechanism (FIG. 58) at thepoint of unapproximation at which anvil head 124 is able to pivot to thetilted reduced profile position. Contact between wing 584 and abutmentmember 580 provides a tactile and/or audible indication that anvil head124 has tilted. If additional force is provided to approximation knob22, wing 584 of screw stop 306 will force abutment member 580 to theretracted position to allow stapling device 10 to move to the fully openposition. In this position, flexible arms 155 are positioned distally ofbushing 209 and anvil assembly 30 can be disengaged from anvil retainer28.

FIGS. 62-74 illustrate another embodiment of the presently disclosedsurgical stapling device shown generally as 600. Stapling device 600 isparticularly suited for use in minimally invasive gastric bypassprocedures. Such a procedure is described in PCT application Serial No.PCT/US01/07105, filed Mar. 5, 2001, which is incorporated herein byreference in its entirety. Alternately, surgical stapling device 600 maybe used in other surgical procedures, especially those procedures inwhich a reduced profile anvil assembly is required or desired.

Referring to FIG. 62, surgical stapling device 600 includes a proximalhandle assembly 602, an elongated body portion 604 including curvedouter tube 604 a, and a distal head portion 606. Since the components ofhandle assembly 602 and body portion 604 are substantially similar tohandle assembly 12 and body portion 14 discussed above, these portionsof surgical stapling device 600 will not be discussed in further detailherein.

Referring to FIGS. 63-65, an anvil assembly 610 is provided forreleasable attachment to surgical stapling device 600. Anvil assembly610 includes an anvil post 612, an anvil head 614, an anvil plate 616, acenter rod 618, a first slide member 620 and a second slide member 622.Anvil head 614 includes a centrally located through bore 624 (FIG. 65)dimensioned to receive anvil post 612, an inner annular recess 626 andan outer annular recess 628. Outer annular recess 628 is configured toreceive anvil plate 616. Anvil plate 616 includes a tab 630 (FIG. 65)which is dimensioned to be received within a slot 632 formed in anvilhead 614. Tab 630 and slot 632 cooperate to position anvil plate 616 inthe proper orientation within outer recess 628. Inner annular recess 626is configured to receive a cutting ring 634 which includes a centralopening 634 a which is dimensioned to be positioned about anvil post 612and a portion of anvil head 614 defining an inner boundary of annularrecess 626.

Anvil post 612 includes a transverse bore 612 a for receiving a pivotmember 638. Pivot member 638 pivotally connects anvil post 612 to oneend of center rod 618 via cooperating bore 618 a formed in center rod618. In one embodiment, pivot member 638 includes a pin or post whichdefines a transverse axis which is spaced laterally from thelongitudinal axis “x” (FIG. 65) defined by center rod 618 such thatanvil head 614 can pivot approximately 90 degrees from an operativeposition (FIG. 68) in which a plane defined by tissue contact surface615 of the anvil head 614 is substantially perpendicular to thelongitudinal axis “x” of center rod 618 to a tilted reduced profileposition (FIG. 63) in which anvil head 614 is substantially parallel tolongitudinal axis “x” of center rod 618. Alternately, other types ofpivot members at a variety of locations in relation to longitudinal axis“x” of center rod 618 may be incorporated into anvil assembly 610. Forexample, as illustrated in FIGS. 64A and 64B, pivot member 638′ foranvil head 614′ may be positioned on the longitudinal axis of center rod618′.

Center rod 618 includes a throughbore 640 (FIG. 64) having a first end642 and a second end 644. In one embodiment, second end 644 includes atleast one opening 646 dimensioned to receive a suture or the like tofacilitate positioning of anvil assembly 610 within a hollow organ.First end 642 of throughbore 640 is dimensioned to slidably receive atleast a portion of first and second slide members 620 and 622 which aremovable in relation to each other. A spring or biasing member, e.g.,coil spring 641, is positioned between first and second slide members620 and 622 to urge the slide members apart or away from each other. Adrive link 652 is pivotally connected at one end to second slide member622 and at the other end to anvil post 612 by pivot members 653 and 655,respectively. A return link 650 is pivotally connected at one end tofirst slide member 620 and at the other end to anvil post 612 by pivotmembers 657 and 659, respectively. Links 650 and 652 are connected toslide members 620 and 622 and anvil post 612 in such a manner that whenbiasing member 641 urges first and second slide members 620 and 622apart, anvil head 614 pivots about pivot member 638 to its tiltedreduced profile position (FIG. 63).

Center rod 618 includes a plurality of flexible arms 671 which define asecond end 644 of throughbore 640 which is dimensioned to releasablyengage a removable trocar, adaptor or anvil retainer as discussed abovewith respect to stapling device 10. A plurality of splines 673 areformed about center rod 618. Splines 673 mesh with grooves (not shown)formed in stapling device 600 as described above to properly align anvilassembly 610 in relation to shell assembly 700 of surgical staplingdevice 600 during approximation of the anvil and shell assemblies.

FIGS. 66 and 67 illustrate the shell assembly 700 and anvil retainerassembly 702 of surgical stapling device 600 (FIG. 62). FIGS. 66 and 67also illustrate the pusher 724 of the firing mechanism of staplingdevice 600. Although not shown in this figure, anvil retainer assembly702 is connected to an approximation mechanism, such as screw extensions34 and 36 (FIG. 6) disclosed above, and pusher 724 is connected to thefiring mechanism of a stapling device, such as firing trigger 20,disclosed above.

Shell assembly 700 includes a shell or housing 710, a pusher back 712, acylindrical knife (not shown), a staple guide 714 and a plurality ofstaples 716. Shell 710 includes an outer housing portion 710 a and aninner housing portion 710 b (FIG. 67). Staple guide 714 is supported inthe distal end of outer housing portion 710 a and includes an annulararray of staple receiving pockets 718 for housing staples 716. Pusherback 712 is slidably supported in shell 710 between outer housingportion 710 a and inner housing portion 710 b between retracted andadvanced positions. Pusher back 712 includes a plurality of fingers 712a which are each slidably received in respective staple pockets 718 instaple guide 714. Pusher back 712 includes a pair of recesses 720 whichreceive detents 722 a formed on flexible fingers 722 of a pusher 724 tosecure pusher 724 to pusher back 712. Pusher back 712 is movable fromits retracted position to its advanced position, in the manner discussedabove with respect to pusher back 186, to eject staples 716 from stapleguide 714.

An elongated hollow bushing 730 is fixedly retained in inner housingportion 710 b of shell 710 using screw threads, a friction fitting, orthe like. Bushing 730 defines a channel 730 a through which anvilretainer assembly 702 reciprocates during approximation andunapproximation of anvil and shell assemblies 610 and 700, respectively.

Anvil retainer assembly 702 includes a two-part assembly having a bodyportion 732 defining a longitudinal throughbore 732 a and a trocar orlocking member 734 slidably received within the longitudinalthroughbore. Longitudinal throughbore 732 a includes a stepped portionor shoulder 736.

Trocar 734 includes a blunt tip 738 at one end thereof and an annularflange or shoulder 740 at the other end thereof. Alternately, a lessblunt, i.e., sharper, or more blunt trocar may be provided. Tip 738 oftrocar 734 extends from a distal end of body portion 732 of the trocarassembly 702 and is movable within throughbore 732 a from an advancedposition to a retracted position. A biasing member, e.g., a coil spring742, is positioned between annular flange 740 and shoulder 736 (FIG. 67)and urges trocar 734 to its retracted position. The proximal end oftrocar 734 includes a transverse slot 744 having a pin or rod 746extending therethrough. Pin 746 is slidably positioned withinlongitudinal slots 747 formed in body portion 732. The distal andproximal ends of slots 747 define the advanced and retracted positionsof trocar 734, respectively.

Body portion 732 of assembly 702 includes an annular protrusion 749 alongitudinal slot 748. Annular protrusion 749 facilitates attachment ofanvil assembly as discussed above. A cam member 750 is pivotallysupported about a pivot member 756 in slot 748 at a position proximal ofpin 746. Cam member 750 includes a distal finger 752 having an angledface and a recess 754 positioned proximally of finger 752 for receivingpin 746 of trocar 734. Pin 746 is urged by coil spring 742 towardsfinger 752. Engagement between the angled face of finger 752 and pin 746urges cam member 750 to pivot about pivot member 756 to allow pin 746 tomove into recess 754.

FIGS. 66A and 66B illustrate an alternate embodiment of anvil retainerassembly 702 shown generally as 7021. Anvil retainer assembly 702′includes a trocar or locking member 734′ having a blunt tip 738′ and abody portion 732′. Anvil retainer assembly 702′ is substantiallyidentical to anvil retainer 702 with the exception that the shape ofbody portion 732′ has been changed to define a smooth concavity 732′a orcoke bottle shape between annular protrusion 749′ and the distal end ofbody portion 732′. The shape permits tissue to slide smoothly over thebody portion 732′ of anvil retainer assembly 702 prior to attachment ofan anvil assembly thereto.

When assembly 702 is positioned within bushing 730 (when surgicalstapling device 600 is not fully approximated), cam member 750, which isurged by trocar pin 746 to a pivoted position, is prevented frompivoting by engagement with the inner walls of bushing 730. In itsnon-pivoted position (FIG. 67), cam member finger 752 engages pin 746 oftrocar 734 to lock trocar 734 in its distal or advanced position. Whenanvil retainer 702 is withdrawn from bushing 730 a distance sufficientto withdraw cam member 750 from bushing 730, engagement between pin 746of trocar 734 and the angled face of finger 752 of cam member 750 movescam member 750 to a pivoted position (FIG. 72). In the pivoted position,pin 746 moves proximally past the angled face of finger 752 into recess754 and trocar 734 is moved from its advanced position to its retractedposition by biasing member 742.

As illustrated in FIG. 67, pusher 724 extends about the proximal end ofbushing 730. In one embodiment, pusher 724 includes a pair of flexiblearms 760 which extend radially inwardly adjacent the proximal end ofbushing 730. Arms 760 are positioned to prevent cam member 750 frompivoting to a position to allow retraction of trocar 734 even when thedevice has been approximated (FIG. 70). However, when the surgicalstapling device is fired, pusher 724 is moved distally and arms 760deform over bushing 730 to permit pivoting of cam member 750 andfacilitate retraction of trocar 734 (FIG. 72). Thus, when pusher 724 isprovided with arms 760, trocar 734 will not move to its retractedposition until device 600 has been approximated and fired.

Referring to FIGS. 68 and 69, anvil assembly 610 is secured to anvilretainer assembly 702 by inserting retractable trocar 734 into bore 642of center rod 618 of anvil assembly 610. Because the anvil retainerassembly 702 is unapproximated when anvil assembly 610 is attached anddevice 600 has yet to be fired, trocar 734 is in its advanced position.When trocar 734, in its advanced position, is inserted into center rodbore 642, tip 738 of trocar 732 engages a base portion 622 a of secondslide member 622 and moves second slide member 622 towards first slidemember 620 to move anvil head 614 from its tilted position to itsapproximated position via links 650 and 652.

Referring to FIGS. 70 and 71, when the anvil assembly 610 and shellassembly 700 are approximated, cam member 750 is prevented from pivotingby bushing 730 and arms 760 of pusher 724. Since cam member 750 is notfree to pivot, finger 752 is positioned to prevent pin 746 from movingproximally within body portion 732 of assembly 702 to prevent retractionof trocar 734. As such, trocar tip 738 engages second slide member 622to retain second slide member 622 in its advanced position. As such,anvil head 614 is retained in the operative, non-tilted position.

Referring to FIGS. 72 and 73, when stapling device 600 is fired andpusher 724 is moved distally about bushing 730, arms 760 are deformedoutwardly away from cam member 750. Engagement between pin 746 and theangled face of finger 752 causes cam member 750 to pivot. When cammember 750 pivots, pin 746 moves proximally into recess 754 of cammember 750 and trocar 734 moves to the retracted position under the biasof spring 742. As trocar 734 moves to its retracted position, biasingmember 641 urges first and second slide members 620 and 622 apart tourge anvil head 614 to its tilted reduced profile position (see FIG.74). Because of the proximity of anvil head 614 to shell assembly 700,anvil head 614 will only move to its tilted reduced profile positionduring unapproximation of the anvil and shell assemblies 610 and 700,respectively.

As discussed above, the surgical stapler is particularly suited for usein minimally invasive gastric bypass procedures. In one method ofperforming a minimally invasive gastric bypass procedure, anvil assembly610 (FIG. 64) of stapling device 600 is provided in its tilted reducedprofile position. The distal end of anvil center rod 618 is secured to ahollow flexible tube (not shown). An adaptor 800 as illustrated in FIG.75 is used to secure anvil center rod 618 to the flexible tube. Adaptor800 includes a first end 802 having a flexible arm 804 formed thereon.Flexible arm 804 includes a distal protrusion 806 having a tapered face806 a which is dimensioned to be received, or snap-fit, into opening 646(FIG. 63) of anvil center rod 618. A release button 808 is provided onflexible arm 804 to be pressed to disengage protrusion 806 from opening646 of anvil center rod 618. A second end 809 of adaptor 800 includescylindrical member 810 having a series of tapered ridges 812. Second end809 is dimensioned to be received within the flexible tube (not shown)to secure adaptor 800 to the flexible tube. Second end 809 may be formedas a separate part from first end 802 and secured thereto using, forexample, a suture (not shown) tied through opening 816. Alternately,first and second ends 802 and 808 can be integrally or monolithicallyformed.

To perform the gastric bypass procedure, ridged second end 809 ofadaptor 800 is inserted into one end of the flexible tube. Adaptor 800is secured to anvil center rod 618 (FIG. 1) by inserting first end 802of adaptor 800 into bore 644 (FIG. 64) of center rod 618 such thatprotrusion 806 is snap-fit into opening 646. Next, the distal free endof the flexible tube is inserted into the mouth and snaked down theesophagus to the surgical site, e.g., stomach. A small incision is madeat the surgical site to allow the leading end of the tube to be pulledthrough the incision to position anvil assembly 614 at the surgicalsite. As the tube is pulled through the incision, the anvil center rod618 is pulled through the incision. Adaptor 800 is disengaged fromcenter rod 618 by pressing on release button 808 to disengage protrusion806 from opening 646 in center rod 618 and pulling on the tube to removeboth the tube and adaptor 800. Anvil center rod 618 is then mounted onstapling device 600. Stapling device 600 can now be operated in itsnormal manner to perform the desired surgical procedure.

FIGS. 75-94 disclose another embodiment of the presently disclosedsurgical stapling device shown generally as 810 including a passivelockout mechanism. Surgical stapling device 810 is substantiallyidentical to stapling device 10 with the exception that proximal handleassembly 12 has been modified to include a passive lockout mechanismwhich operates in association with trigger lock 826 to preventunclamping of a clamped or approximated stapling device after thetrigger lock has been pivoted to its unlocked position but prior tofiring of the stapling device. Only the passive lockout mechanism andthose elements of surgical stapling device 810 which operate inassociation with the passive lockout mechanism will be described indetail below.

Referring to FIGS. 75 and 76, surgical stapling device 810 includes aproximal handle assembly 812, an elongated curved central body portion814 and a distal head portion 816. Alternately, elongated central bodyportion may include a straight shaft more suitable for other surgicalprocedures, e.g., hemorrhoidectomies, mucosectomies, etc. Handleassembly 812 includes a stationary handle 818, a firing trigger 820, arotatable approximation knob 822 and a pivotally mounted trigger lock826. Distal head portion 816 includes an anvil assembly 830 and a shellassembly 831. As discussed above, anvil assembly 830 is movablysupported in relation to shell assembly 831 between spaced and clampedor approximated positions.

Referring to 77-79, the passive lockout mechanism includes a lockingplate 834 and a biasing member 836. Locking plate 834 includes a body838 defining a cylindrical bore 840, a release tab 842 and a locking tab843 having a pair of lateral extensions 844. In one embodiment, each oflateral extensions 844 is arc-shaped. Cylindrical bore 840 isdimensioned to be positioned about one of two pivot members 846 formedon trigger lock 826 such that locking plate 834 is rotatableindependently of trigger lock 826 about the pivot member 846. Triggerlock 826 includes a pair of slots 848 dimensioned to slidably receivelateral extensions 844. In one embodiment, slots 848 are arc-shaped andhave a radius of curvature substantially equal to the radius ofcurvature of lateral extensions 844. Trigger lock 826 also includes anabutment member 853 which will be discussed in further detail below.

Referring also to FIGS. 81 and 82, in one embodiment, a recess 849 ispositioned between lateral extensions 844 and a pair of spaced upper andlower protrusions 850 a and 850 b are positioned between slots 848 oftrigger lock 826. Each protrusion 850 a and 850 b is dimensioned to bereleasably received in recess 849, each protrusion functioning to indexthe movement of interlock plate 834 with that of the trigger lock 826and to retain locking plate 834 at one of two positions in relation totrigger lock 826.

Referring specifically to FIG. 79, pivot members 846 of trigger lock 826are dimensioned to be received within bores 832 of handle sections 818 aand 818 b. As discussed above with respect to trigger lock 26, pivotmembers 846 can be T-shaped and dimensioned to frictionally engage aninner wall defining bore 832 to prevent free rotation of trigger lock826 between handle sections 818 a and 818 b. Alternately, use of otherpivot member configurations as described above is envisioned.

In use, locking plate 834 is rotatably supported about one of pivotmembers 846 of trigger lock 826 by positioning pivot member 846 throughcylindrical bore 840 of locking plate 834 and positioning extensions 844through respective slots 848 formed in trigger lock 826. In theassembled condition, locking plate 834 is positioned between triggerlock 826 and handle half-section 818 a. Slots 848 have a length which isgreater than the length of extensions 844 such that extensions 844 areable to slide along slots 848 and locking plate 834 can rotate inrelation to trigger lock 826. Biasing member 836 is positioned aboutpivot member 846 between locking plate 834 and handle half-section 818 ato urge locking plate 834 into engagement with trigger lock 826, i.e.,one of protrusions 850 is urged into recess 849.

Referring to FIG. 80, screw stop 860 is substantially identical to screwstop 306 as disclosed above with the exception that screw stop 860includes a tab or third engagement member 862. Third engagement member862 is positioned to engage locking tab 843 of locking plate 834 aftertrigger lock 826 has been unlocked if an attempt is made to unclampdevice 810 prior to firing of device 810 as will be described in detailbelow.

Operation of the passive lockout mechanism will now be described indetail with reference to FIGS. 83-94.

Referring to FIGS. 83-86, when stapling device 810 is in itsunapproximated, unfired condition, anvil assembly 830 is spaced fromshell assembly 831 and screw stop 860 is positioned in a distal end ofhandle assembly 812 (FIG. 83). As illustrated in FIG. 84, lateralextensions 844 of locking plate 834 are positioned adjacent an upper endof slots 848. As shown in phantom, upper protrusion 850 a is positionedwithin recess 849 to releasably secure locking plate 834 to trigger lock826.

Referring to FIGS. 87-90, when surgical stapling device 810 isapproximated by rotating approximation knob 822 to move anvil assembly830 into juxtaposed alignment with shell assembly 831, screw stop 860 ismoved toward the proximal end of handle assembly 812 (FIG. 87). Whenthis occurs, lockout member 530 is moved to a position to unlock triggerlock 826 as discussed above with respect to surgical stapling device 10.As such, trigger lock 826 can be pivoted in a direction indicated byarrow “V” in FIG. 87 from a position preventing operation of firingtrigger 820 (FIG. 83) to an unlocked position substantially aligned withstationary handle 818.

As trigger lock 826 is pivoted to the unlocked position, locking plate834 is pivoted with trigger lock 826 in the direction indicated by arrow“W” in FIG. 88. This occurs because locking plate 834 is frictionallyheld against trigger lock 826 by biasing member 836 and by engagement oftrigger lock protrusion 850 a in recess 849 of locking plate 834. Inthis position, locking tab 843 of interlock plate 834 is positioned toabut engagement member 862 to obstruct advancement of screw stop 860(FIG. 89). As illustrated, engagement member 822 may include a concavity862 a for receiving a curved upper surface of second tab 843. Abutmentmember 853 of trigger lock 826 is also positioned to engage locking tab843 to prevent further clockwise pivoting of locking plate 834. In thisposition of trigger lock 826 and locking plate 834, surgical staplingdevice 810 is prevented from being unclamped or unapproximated. Morespecifically, if rotation knob 822 is rotated to unapproximate anvilassembly 830 from shell assembly 831, screw stop 860, in the mannerdiscussed above with respect to screw stop 306, will be moved distallywithin handle assembly 812. As screw stop begins to move distally,however, third engagement member 862 formed on screw stop 860 abutslocking tab 843 of locking plate 834 to prevent distal movement of screwstop 860 within handle assembly 812 (See FIGS. 89 and 90). As seen inFIG. 89, abutment member 853 on trigger lock 826 acts as a stop toprevent engagement member 862 of screw stop 860 from pushing second tab843 of locking plate 834 out of the path of screw stop 860. As such,locking plate 834 prevents an operator of a surgical stapling device 810from unapproximating or unclamping tissue from between anvil assembly830 and shell assembly 831 after the surgical stapling device 810 hasbeen approximated and the trigger lock 826 has been moved to an unlockedposition.

Referring to FIGS. 91-94, when firing trigger 820 is actuated to firesurgical stapling device 810, firing trigger 820 is moved in thedirection indicated by arrow “Y” in FIG. 91 towards stationary handle818. As firing trigger 820 moves towards stationary handle 818, arelease member 880 supported on firing trigger 820 engages release tab842 of locking plate 834 to pivot locking plate 834 in the directionindicated by arrow “X” in FIG. 92. Since firing trigger 820 engagestrigger lock 826 as it is moved towards stationary handle 818 andprevents trigger lock 826 from pivoting, locking plate 834 pivotsindependently of trigger lock 826. As such, protrusion 850 a isdisengaged from recess 849 and protrusion 850 b moves into recess 849.Simultaneously, lateral extensions 844 of locking plate 834 move to anopposite end of respective slots 848 of trigger lock 826. As lockingplate 834 pivots, locking tab 843 of locking plate 834 is moved to aposition which no longer obstructs advancement of screw stop 860 withinhandle assembly 812. As a result, after stapling device 810 has beenfired, rotatable knob 822 can be actuated to unapproximate anvilassembly 830 in relation to shell assembly 831.

FIGS. 95 and 96 illustrate the handle assembly 912 of another embodimentof the presently disclosed surgical stapling device 900. Handle assembly912 is substantially the same as handle assembly 812 disclosed abovewith the exception that firing trigger 920 has been lengthened andwidened. As illustrated in FIG. 95, the proximal end 920 a of firingtrigger 920 is positioned proximally of the distal end of approximationknob 922. As illustrated in FIG. 96, the width of firing trigger 920adjacent its gripping surface is about seventy-five percent of the widthof stationary handle 918. By increasing the length of firing trigger920, the moment arm is increased and the firing forces required to firesurgical stapling device 900 are substantially reduced. Further, byincreasing the width of firing trigger 920, the force applied by asurgeons hand on firing trigger 920 are evenly distributed over a largersurface area of the surgeons hand. As a result, a surgeon is able tomore-comfortably fire the stapling device.

It will be understood that various modifications may be made to theembodiments disclosed herein. For example, although the descriptionrefers exclusively to staples, it is envisioned that staples may includedifferent types of tissue fasteners including two-part fasteners. In astapling device for applying two-part fastener, the anvil assembly ofthe stapling device would support one part of each two-part fastenerwhile the shell assembly would support the other part of each two partfastener. Further, although the improvements disclosed herein aredisclosed in association with a particular surgical stapling device,these improvements may be incorporated into any known surgical staplingdevice including those devices disclosed in the following U.S. Pat. Nos.5,915,616, 5,836,503, 5,588,579, 5,350,104, 5,333,773 and 5,312,024.Therefore, the above description should not be construed as limiting,but merely as exemplifications of embodiments. Those skilled in the artwill envision other modifications within the scope and spirit of theclaims appended hereto.

1. A tiltable anvil assembly comprising: a center rod; a head assemblyincluding a housing, a post, an anvil plate having staple deformingpockets, and a backup member, the head assembly being pivotally securedto the center rod and pivotal in relation to the center rod between anoperative position and a tilted position, wherein the backup member ismovable about the post from a first position in which a portion of thebackup member is positioned to prevent movement of the head assemblyfrom the operative position to the tilted position, to a second positionin which the backup member is positioned to permit movement of the headassembly in relation to the center rod from the operative position tothe tilted position, and further including a retainer member positionedin the head assembly to prevent movement of the backup member from thefirst position to the second position until a predetermined force hasbeen applied to the backup member, wherein the retainer member includesa plurality of deformable tabs positioned to engage the backup memberand deform in response to the predetermined force applied to the backupmember.
 2. A tiltable anvil assembly according to claim 48, wherein theretainer member is positioned in the head assembly between the housingand the backup member.
 3. A tiltable anvil assembly according to claim2, wherein the housing and defines an annular recess, the retainermember being positioned in the annular recess.
 4. A tiltable anvilassembly according to claim 3, wherein the retainer member includes anannular body which is positioned about the post
 5. A tiltable anvilassembly according to claim 1, further comprising a cutting ring securedto a proximal face of the backup plate.
 6. A tiltable anvil assemblyaccording to claim 5, wherein the backup plate includes at least onefinger positioned to engage a distal surface of the center rod when thebackup member is in its first position to prevent pivotal movement ofthe head assembly in relation to the center rod.
 7. A tiltable anvilassembly according to claim 6, wherein the cutting ring is formed from asofter material than the backup plate.
 8. A tiltable anvil assemblyaccording to claim 7, wherein the cutting ring is formed frompolyethylene and the backup plate is formed from a metal.
 9. A tiltableanvil assembly according to claim 1, wherein the predetermined force isbetween about ten pounds and about ninety pounds.
 10. A tiltable anvilassembly according to claim 1, wherein the center rod defines alongitudinal axis and the pivot axis is offset from the longitudinalaxis of the center rod.
 11. A tiltable anvil assembly according to claim1, wherein the center rod defines a longitudinal axis and the pivot axisintersects the longitudinal axis of the center rod.
 12. A surgicalstapling assembly comprising: a handle assembly; an elongated bodyportion; and a distal head portion including a shell assembly supportinga plurality of staples and a tiltable anvil assembly, the tiltable anvilassembly having a center rod and a head assembly pivotal with respect tothe center rod from an operative position to a tilted position, the headassembly including a housing, a post, an anvil plate and a backupmember, wherein the backup member is movable about the post from a firstposition preventing pivotal movement of the head assembly from theoperative position to the tilted position to a second positionpermitting movement of the head assembly from the operative position tothe tilted position, and a retainer member supported on the headassembly at a position to prevent movement of the backup member from itsfirst position to its second position until a predetermined force hasbeen applied to the backup member, wherein the retainer member includesa plurality of deformable tabs deformable by movement of the backupmember in response to the predetermined force applied to the backupmember.
 13. A surgical stapling assembly according to claim 12, whereinthe predetermined force is between about ten pounds and about ninetypounds.
 14. A surgical stapling assembly according to claim 12, whereinthe retainer member is positioned in the head assembly between thehousing and the backup member.
 15. A surgical stapling assemblyaccording to claim 14, wherein the retainer member includes an annularbody which is positioned about the post.
 16. A surgical staplingassembly according to claim 15, wherein the backup member is positionedto abut the plurality of deformable tabs such that movement of thebackup member from the first position to the second position effectsdeformation of the deformable tabs.
 17. The surgical stapling assemblyaccording to claim 12, further comprising a retainer clip having aportion movable in front of the backup member after firing of thestaples.
 18. The surgical stapling assembly according to claim 17wherein the retainer clip includes a pair of flexible arms, the flexiblearms movable in front of the backup member.